The present invention relates to mattress pads or cushions or mattress toppers that are commonly formed from polyurethane foam. Such pads are intended to be placed on top of existing mattresses to provide more comfortable support to a reclining person.
Presently, mattress pads, like fitted sheets, are available in predetermined lengths and widths that conform to the lengths and widths of mattresses, i.e., twin, full, queen and king. Mattress pads are factory cut to match the "standard" predetermined lengths and widths of conventional mattress sizes. The various sized pads are then packaged, separately marked as twin, full, queen and king.
A single mattress pad where the consumer could readily adjust the size to fit one or more particular applications has not been available. Nor have mattress pads with perforations or cutting guides to allow the consumer to adjust the size of the pad been available or disclosed in the art.
A method for perforating foam mattress pads is shown in U.S. Pat. No. 4,097,210 (Romanillos). However, Romanillos teaches perforating the foam during the foam forming process to increase the escape of gas and allow a smooth flat top foam surface (col. 1, lines 56-60).
In U.S. Pat. No. 4,825,488 (Bedford) a foam support pad for nonambulatory persons has portions of the pad that are detachable along perforations to allow insertion of pad sections that include special fans to give increased air circulation beneath the patient (col. 2, lines 47-54). Bedford does not teach adjustment of the size of the pad to fit on various-sized mattresses.
U.S. Pat. No. 4,686,725 (Mitchell) discloses a mattress cushion that may be split into two or more units by the manufacturer at the factory for convenience in packaging, shipping or manufacturing (Col. 4, line 62). Mitchell does not disclose a pad that may be reduced in size by removing portions of the foam material along perforations or cutting guides.
Convoluting of polyurethane foam is well known. Convoluting provides the foam pad with a contoured surface of peaks and troughs or ridges and troughs. Examples of convoluting processes are described in U.S. Pat. Nos. 2,902,091 (Dahle), 3,197,357 (Schulpen), 3,431,802 (Schulpen II), and 4,603,445 (Spann).
Punching ventilation holes through the thickness of a mattress pad in a second step after the pad has been formed by convoluting a foam slab is taught in the art. See, e.g. U.S. Pat. No. 4,686,724 (Bedford) at col. 2, lines 30-35.
Ventilation holes may also be cut into the foam during a specialized convoluting method using an auxiliary with the foam pad that is to be convoluted. As described in U.S. Pat. No. 4,603,445 (Spann), at Col. 5, lines 46-55, for example, the auxiliary pad "increases" the foam slab thickness that passes through the convoluter rolls. The increase in thickness permits the convoluter to cut or punch holes through the foam pad. Thereafter, the auxiliary pad is peeled away to reveal the pad with voids or vents (FIGS. 11 and 12 of Spann). Spann also suggests that smaller ventilation holes or voids 43 may be provided in the pad if less compression is applied when the foam is sandwiched between auxiliary pads and this sandwich is passed through the convoluter rolls (Col. 6, lines 29-33).
One of the objects of the present invention is to form a size adjusting mattress pad where a tearing or cutting guide is provided in the mattress pad. A further object of the present invention is to provide the tearing or cutting guide in a convoluted foam mattress pad by forming holes in the trough between the peaks of the convoluted mattress pad when the foam slab is passed through the convoluter rolls and cut with the knife blade adjacent to those rolls.